SoVRMLSpotLight Class Reference
[VRML97 nodes]
Node representing a spotlight source.
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#include <Inventor/VRMLnodes/SoVRMLSpotLight.h>
Public Member Functions | |
| virtual SoType | getTypeId () const |
| SoVRMLSpotLight () | |
Static Public Member Functions | |
| static SoType | getClassTypeId () |
Public Attributes | |
| SoSFVec3f | location |
| SoSFVec3f | direction |
| SoSFFloat | beamWidth |
| SoSFFloat | cutOffAngle |
| SoSFFloat | radius |
| SoSFVec3f | attenuation |
Detailed Description
Node representing a spotlight source.
The SoVRMLSpotLight node defines a light source that emits light from a specific point along a specific direction vector and constrained within a solid angle. SoVRMLSpotlights may illuminate geometry nodes that respond to light sources and intersect the solid angle. SoVRMLSpotlights are specified in their local coordinate system and are affected by parent transformations.
Note: SoVRMLSpotLights only illuminate objects in their enclosing parent group (similar to Directional lights). This is a slight deviation from the behavior described by the VRML97 specification.
NOTE: This class does not exist in Open Inventor 10.0 and later.VRML97 SPECIFICATION
- This section describes the expected behavior of the node in a conforming VRML97 browser application. In some cases, the application is responsible for implementing portions of the expected behavior. Open Inventor viewer classes and IVF classes implement some of the application behaviors.
This section may reference portions of the VRML97 specification that are not present in this help file. The complete VRML97 spec is available at http://www.web3d.org .
The SoVRMLSpotLight node defines a light source that emits light from a specific point along a specific direction vector and constrained within a solid angle. SoVRMLSpotlights may illuminate geometry nodes that respond to light sources and intersect the solid angle. SoVRMLSpotlights are specified in their local coordinate system and are affected by parent transformations.
See "Concepts - Light Sources" for a detailed description of ambientIntensity , color , intensity , and VRML's lighting equations. See "Concepts - Lighting Model" for a detailed description of the VRML lighting equations.
The location field specifies a translation offset of the center point of the light source from the light's local coordinate system origin. This point is the apex of the solid angle which bounds light emission from the given light source. The direction field specifies the direction vector of the light's central axis defined in its own local coordinate system. The on field specifies whether the light source emits light--if TRUE, then the light source is emitting light and may illuminate geometry in the scene, if FALSE it does not emit light and does not illuminate any geometry. The radius field specifies the radial extent of the solid angle and the maximum distance from location than may be illuminated by the light source - the light source does not emit light outside this radius. The radius must be >= 0.0.
The cutOffAngle field specifies the outer bound of the solid angle. The light source does not emit light outside of this solid angle. The beamWidth field specifies an inner solid angle in which the light source emits light at uniform full intensity. The light source's emission intensity drops off from the inner solid angle (beamWidth) to the outer solid angle (cutOffAngle). The drop off function from the inner angle to the outer angle is a cosine raised to a power function:
intensity(angle) = intensity * (cosine(angle) ** exponent)
where exponent = 0.5*log(0.5)/log(cos(beamWidth)),
intensity is the SpotLight's field value,
intensity(angle) is the light intensity at an arbitrary
angle from the direction vector,
and angle ranges from 0.0 at central axis to cutOffAngle.
If beamWidth > cutOffAngle, then beamWidth is assumed to be equal to cutOffAngle and the light source emits full intensity within the entire solid angle defined by cutOffAngle. Both beamWidth and cutOffAngle must be greater than 0.0 and less than or equal to pi/2. See the figure below for an illustration of the SoVRMLSpotLight's field semantics (note: this example uses the default attenuation).
The light's illumination falls off with distance as specified by three attenuation coefficients. The attenuation factor is 1/( attenuation [0] + attenuation [1]*r + attenuation [2]*r^2) , where r is the distance of the light to the surface being illuminated. The default is no attenuation. An attenuation value of 0 0 0 is identical to 1 0 0 . Attenuation values must be >= 0.0.
FILE FORMAT/DEFAULT
- VRMLSpotLight {
| ambientIntensity | 0 |
| attenuation | 1 0 0 |
| beamWidth | 1.570796 |
| color | 1 1 1 |
| cutOffAngle | 0.785398 |
| direction | 0 0 -1 |
| intensity | 1 |
| location | 0 0 0 |
| on | TRUE |
| radius | 100 |
| metadata | NULL |
ACTION BEHAVIOR
EVENTS
- Deprecated:
-
Deprecated since Open Inventor 9500
The VRML API is no longer supported. See section http://oivdoc95.vsg3d.com/content/compatibility-notes-4#Deprecation of the Reference Manual. - Inventor/VRMLnodes/SoVRMLSpotLight.h
eventIn
| SoSFFloat | set_ambientIntensity |
| SoSFVec3f | set_attenuation |
| SoSFFloat | set_beamWidth |
| SoSFColor | set_color |
| SoSFFloat | set_cutOffAngle |
| SoSFVec3f | set_direction |
| SoSFFloat | set_intensity |
| SoSFVec3f | set_location |
| SoSFBool | set_on |
| SoSFFloat | set_radius (Note: Not implemented) |
| SoSFNode | set_metadata |
eventOut
| SoSFFloat | ambientIntensity_changed |
| SoSFVec3f | attenuation_changed |
| SoSFFloat | beamWidth_changed |
| SoSFColor | color_changed |
| SoSFFloat | cutOffAngle_changed |
| SoSFVec3f | direction_changed |
| SoSFFloat | intensity_changed |
| SoSFVec3f | location_changed |
| SoSFBool | on_changed |
| SoSFFloat | radius_changed (Note: Not implemented) |
| SoSFNode | metadata_changed |
Constructor & Destructor Documentation
| SoVRMLSpotLight::SoVRMLSpotLight | ( | ) |
Constructor.
Member Function Documentation
| static SoType SoVRMLSpotLight::getClassTypeId | ( | ) | [static] |
Returns the type identifier for this class.
Reimplemented from SoVRMLLight.
| virtual SoType SoVRMLSpotLight::getTypeId | ( | ) | const [virtual] |
Returns the type identifier for this specific instance.
Reimplemented from SoVRMLLight.
Member Data Documentation
Attenuation coefficients.
Inner solid angle of illumination.
Outer solid angle of illumination.
Direction vector of the light's central axis.
Specifies a translation offset of the centerpoint of the light source from the light's local coordinate system origin.
(Note: Not implemented) Specifies the radial extent of the solid angle and the maximum distances from location that may be illuminated by the light source.
The documentation for this class was generated from the following file: